Ivan Toney passed a medical on Friday ahead of a proposed £40million move from Brentford to Al Ahli.
The Saudi Arabian club, who have until Monday to close their business, sparked life into transfer deadline day by making offers for both Toney and Chelsea target Victor Osimhen of Napoli - but can only sign one.
The question mark for Toney remained whether to take the lucrative three-year deal now to suit Brentford or wait until January when he could have greater options.
Arsenal were previously tempted by Toney's availability but later decided against pursuing a transfer as Brentford held out for a huge fee for the England international.
Brentford later accepted the £40m bid made by the Saudi Pro League side as they recognise it is their best chance of making a profit on their star striker.
Brentford striker Ivan Toney has reportedly agreed to move to Saudi side Al-Ahli for a transfer fee of £40million
Toney was spotted arriving for his medical in London earlier in the day that has now been completed with his transfer to the Middle East set to be confirmed.
It was a tense summer for Toney, who was keen to a departure from the Bees, where he spent the last four years after a transfer from Peterborough United.
The Red Devils faced competition from Stamford Bridge after it was revealed that Chelsea also showed interest in securing another deal before the transfer window deadline.
Despite criticism regarding the size of Chelsea's squad, Toney was not the only player they were considering.
Enzo Maresca's group was also looking to negotiate a one-year loan deal with an option to buy with Napoli for Victor Osimhen's transfer.
The contract of the centre-forward was set to expire in 2026, and Gli Azzurri planned to sell the player before the summer transfer window deadline in Italy, which closes on Friday evening.
Similar to Osimhen, Toney was not included in his team's last matchday squad of the season.
Speaking on Toney's absence, Brentford head coach Thomas Frank admitted that the player's future was uncertain: 'He could be here after August 30 and he could not be here.
'Basically, everything is up in the air. I've said the whole time that if he's here I'm very happy, if he's not here then I'm happy on his behalf.